Two Navy destroyers and dozens of Marines and CIA agents were mobilized Thursday after militants killed the U.S. ambassador to Libya and three other Americans.
The USS Laboon was in position off Libya's coast and the USS McFaul was en route from the Strait of Gibraltar, arriving in a few days, U.S. officials said.
The guided-missile destroyers are equipped with long-range, satellite-guided Tomahawk cruise missiles that could be used if a strike is ordered.
U.S. and British forces fired nearly 300 Tomahawk missiles against Libyan targets in March 2011 during the revolution that forced the ouster of strongman Moammar Gadhafi.
The approximately 50 elite Marines dispatched to Tripoli were in place Thursday providing counter-terrorism security at the U.S. Embassy, officials said.
The Marine unit is known as the Fleet Anti-terrorism Security Team, part of the Marine Corps Security Force Regiment, a dedicated security and counter-terrorism unit often guarding high-value U.S. Navy installations, notably those containing nuclear vessels and weapons.
Besides the CIA, the FBI and other agencies were marshaled to identify and pursue the attackers, officials said. Their efforts might be aided by U.S. drones that have continued to conduct surveillance flights over Libya since Tripoli fell 13 months ago, The Washington Post reported.
Islamist militants armed with anti-aircraft weapons and rocket-propelled grenades stormed the U.S. Consulate in Benghazi, Libya, late Tuesday, killing U.S. Ambassador Christopher Stevens and three members of his staff in an intense, 4-hour firefight for control of the mission, U.S. and Libyan officials said.
Stevens' body was not located until dawn Wednesday, when he was found dead at a Benghazi hospital, U.S. and Libyan officials told The New York Times.
It was the first time since 1979 that a U.S. ambassador was killed in a violent assault.
Preliminary reports speculated the violence grew spontaneously out of anger over a U.S.-made amateur video mocking Islam and the Prophet Muhammad. But U.S., Libyan and European officials later cast doubt on that theory, with some suggesting the attackers took advantage of an anti-U.S. protest to stage a prearranged attack.
Officials told several news organizations the attackers were well organized, well trained and heavily armed, and they appeared to have some level of advance planning.
Officials declined to say if the attack, which occurred on the anniversary of the Sept. 11 terrorist attacks, was related to the 2001 attacks.
"Make no mistake, justice will be done," President Barack Obama said in a somber appearance in the White House Rose Garden Wednesday.
Libyan leaders in Tripoli also vowed to track down the attackers and stressed their unity with Washington.
Libyan de facto head of state Yussef Magariaf, president of Libya's newly elected General National Congress, offered "an apology to the United States and the Arab people, if not the whole world, for what happened."
He pledged new measures to ensure the security of foreign diplomats and companies.
"We together with the United States government are on the same side, standing in a united front in the face of these murderous outlaws," he said.
Residents of Tripoli and Benghazi staged demonstrations Wednesday night in support of the United States, condemning the attack and expressing their sorrow at the embassy deaths.
Photos of the demonstrations were posted by BuzzFeed at tinyurl.com/pro-USdemos.
Meanwhile, in neighboring Egypt, riot police fired warning shots and tear gas early Thursday outside the U.S. Embassy in Cairo to keep hundreds of protesters away from the building's perimeter, witnesses said.
Demonstrators threw rocks and Molotov cocktails as police tried to disperse them, CNN reported. More than a dozen people were injured in the clashes.
The violence followed demonstrations outside the embassy Wednesday. Those demonstrations came a day after protesters in an angry crowd of some 2,000 people scaled the U.S. Embassy wall Tuesday a few hours before the Benghazi attack.
The protesters pulled down an American flag and burned it, replacing the flag with a black banner with white letters reading, "There is no god but God and Muhammad is His Messenger," a phrase favored by ultraconservative Muslims and militants.
